Based on an analysis of some 300 class and overall title winning drug-free bodybuilders and strength athletes from 1947 to 2007 the following equation, predicting the maximum lean body mass someone of a given height and bone-structure can achieve without the use of anabolic drugs, was derived. (There is a link at the end of this article to an online calculator based on all of the formulae presented here).

H = Height in inches
A = Ankle circumference at the smallest point
W = Wrist circumference measured on the hand side of the styloid process.
(The styloid process is the bony lump on the outside of your wrist.)
%bf = The body fat percentage at which you want to predict your maximum lean body mass

So, using this equation, for a 5’9″ (69 inches) tall bodybuilder at 10% body fat with 7.0″ wrists and 8.7″ ankles the equation would yield:

173.7 Pounds (Maximum lean mass)

To convert maximum lean body mass to maximum bodyweight at any given body fat, use this equation: